Capacitive sensing apparatus designs

ABSTRACT

One type of capacitive sensing apparatus has a sensing element that includes a first portion and a second portion adjacent opposite edges of a sensing region. Signals from the first and second portions are combined. Another type of apparatus includes: a first sensing element including first and second portions; a second sensing element including third and fourth portions; and a third sensing element including fifth and sixth portions. The first, third and fifth portions form a first pattern, and the second, fourth and sixth portions form a second pattern. The patterns are bilaterally symmetrical about a median of a sensing region. In another type of apparatus, an electrical conductor coupled to a first sensing element passes through a gap in a second sensing element. An electrical conductor coupled to the second sensing element is dimensioned such that a capacitive coupling to the second sensing element is compensated for the gap.

BACKGROUND

Conventional computing devices provide a user with several ways to inputa choice or a selection. For example, a user can use one or more keys ofan alphanumeric keyboard communicatively connected to the computingdevice in order to indicate a choice or selection. Additionally, a usercan use a cursor control device communicatively connected to thecomputing device to indicate a choice. Also, a user can use a microphonecommunicatively connected to the computing device to audibly indicate aparticular selection. Moreover, touch-sensing technology can be used toprovide an input selection to a computing device or other electronicdevice.

Within the broad category of touch sensing technology there existcapacitive sensing touch sensors. Among conventional capacitive touchsensors, there are different sensing technologies. For example, onesensing technology involves the use of sensing electrodes formed intriangular shapes wherein the direction of each triangle pointalternates. However, there are disadvantages associated with thistechnique. For instance, one of the disadvantages is that as a finger(or object) moves towards the wide end of a first triangular shapedelectrode and the narrow point of a second triangular shaped electrode,the narrow point electrode does not provide a quality signal because ofits inherent signal-to-noise ratio. As such, this can be referred to assensing geometry that induces signal-to-noise ratio concerns.

Another sensing technology uses a grid of conductive elements that crossover one another. While this design offers ease of signalinterpretation, it also has the disadvantage of higher manufacturingcost. A further disadvantage affects multiple-layer sensors, as eachlayer degrades optical clarity of a capacitive touch sensor.

Another factor to consider in the design of a capacitive sensingapparatus is that the sensed position of a finger or object relative tothe touch sensor should be unambiguous. That is, for example, theresponse of the sensing apparatus to a finger at any location on a touchsensor should be different from the response at other locations on thetouch sensor.

Thus, a capacitive sensing apparatus that addresses one or more of theabove-mentioned issues would be advantageous.

SUMMARY

Embodiments in accordance with the present invention pertain tocapacitive sensing apparatuses that address one or more of the issuesstated above.

In one embodiment, a capacitive sensing apparatus includes a number ofelectrically conductive sensing elements that have widths that vary andlengths that traverse a sensing region. The sensing elements include atleast a first sensing element, a second sensing element and a thirdsensing element. The third sensing element includes a firstvariable-width portion disposed adjacent a first edge of the sensingregion, and a second variable-width portion disposed adjacent a secondedge of the sensing region opposite the first edge. A first sensorsignal is output from the first sensing element and a second sensorsignal is output from the second sensing element. The sensor signaloutput from the first portion and the sensor signal output from thesecond portion are combined to provide a third sensor signal. Accordingto the present embodiment, the potential for an ambiguous sensorresponse is reduced or eliminated.

In another embodiment, a capacitive sensing apparatus includes a numberof electrically conductive sensing elements that have widths that varyand lengths that traverse a sensing region. The sensing elementsinclude: a first sensing element including a first variable-widthportion and a second variable-width portion that produce a combinedfirst sensor signal; a second sensing element including a thirdvariable-width portion and a fourth variable-width portion that producea combined second sensor signal; and a third sensing element including afifth variable-width portion and a sixth variable-width portion thatproduce a combined third sensor signal. The first, third and fifthvariable-width portions are arranged in a first pattern, and the second,fourth and sixth variable-width portions are arranged in a secondpattern. The first pattern and the second pattem are bilaterallysymmetrical about a median that is substantially equidistant fromopposite edges of the sensing region. According to the presentembodiment, the areas and the sensitivities of the sensing elements areessentially the same.

In yet another embodiment, a capacitive sensing apparatus includes atleast a first sensing element and a second sensing element. The secondsensing element has a first gap. A first electrical conductor coupled tothe first sensing element passes through the first gap. A secondelectrical conductor coupled to the second sensing element isdimensioned such that a capacitive coupling to the second sensingelement is compensated for the first gap. According to the presentembodiment, the sensing apparatus can be built in a single layer ofconductive material, reducing manufacturing costs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exemplary capacitive touch sensor device that can beimplemented to include one or more embodiments of the invention.

FIG. 2 illustrates an exemplary capacitive sensor pattern in accordancewith embodiments of the invention.

FIG. 3 illustrates another exemplary capacitive sensor pattern inaccordance with embodiments of the invention.

FIG. 4 illustrates an exemplary signal strength chart along with itsconversion into polar coordinates in accordance with embodiments of theinvention.

FIG. 5 illustrates yet another exemplary capacitive sensor pattern inaccordance with embodiments of the invention.

FIG. 6 illustrates still another exemplary capacitive sensor pattern inaccordance with embodiments of the invention.

FIG. 7 illustrates another exemplary capacitive sensor pattern inaccordance with embodiments of the invention.

FIG. 8 illustrates yet another exemplary capacitive sensor pattern inaccordance with embodiments of the invention.

FIG. 9 illustrates an exemplary loop capacitive sensor pattern inaccordance with embodiments of the invention.

FIG. 10 illustrates another exemplary loop capacitive sensor pattern inaccordance with embodiments of the invention.

FIG. 11 illustrates yet another exemplary loop capacitive sensor patternin accordance with embodiments of the invention.

FIG. 12 illustrates still another exemplary loop capacitive sensorpattern in accordance with embodiments of the invention.

FIG. 13 illustrates an exemplary “fishbone” capacitive sensor pattern inaccordance with embodiments of the invention.

FIG. 14 illustrates another exemplary “fishbone” capacitive sensorpattern in accordance with embodiments of the invention.

FIG. 15 illustrates yet another exemplary “fishbone” capacitive sensorpattern in accordance with embodiments of the invention.

FIG. 16 illustrates still another exemplary “fishbone” capacitive sensorpattern in accordance with embodiments of the invention.

FIG. 17 illustrates another exemplary capacitive sensor pattern inaccordance with embodiments of the present invention.

FIG. 18 illustrates how sensor signals in the pattern of FIG. 17 can becombined in accordance with embodiments of the present invention.

FIG. 19 illustrates another exemplary capacitive sensor pattern inaccordance with embodiments of the present invention.

FIG. 20 illustrates another exemplary capacitive sensor pattern inaccordance with embodiments of the present invention.

FIG. 21 illustrates a close-up of a portion of the pattern of FIG. 20 inaccordance with embodiments of the present invention.

The drawings referred to in this description should not be understood asbeing drawn to scale except if specifically noted.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of the invention,examples of which are illustrated in the accompanying drawings. Whilethe invention will be described in conjunction with embodiments, it willbe understood that they are not intended to limit the invention to theseembodiments. On the contrary, the invention is intended to coveralternatives, modifications and equivalents, which may be includedwithin the spirit and scope of the invention as defined by the appendedclaims. Furthermore, in the following detailed description of thepresent invention, numerous specific details are set forth in order toprovide a thorough understanding of the present invention. However, itwill be obvious to one of ordinary skill in the art that the presentinvention may be practiced without these specific details. In otherinstances, well known methods, procedures, components, and circuits havenot been described in detail as not to unnecessarily obscure aspects ofthe present invention.

FIG. 1 is a plan view of an exemplary two-dimensional capacitive sensorapparatus 100 that can be implemented to include one or more embodimentsof the present invention. The capacitive sensor apparatus 100 can beutilized to communicate user input (e.g., using a user's finger or aprobe) to a computing device or other electronic device. For example,capacitive sensor apparatus 100 can be implemented as a capacitive touchsensor device that can be placed over an underlying image or aninformation display device (not shown). In this manner, a user wouldview the underlying image or information display by looking through thesubstantially transparent sensing region 108 of capacitive sensorapparatus 100 as shown. One or more embodiments in accordance with thepresent invention can be incorporated with a capacitive touch sensordevice similar to capacitive sensor apparatus 100.

The capacitive sensor apparatus 100 when implemented as a touch sensorcan include a substantially transparent substrate 102 having a first setof conductive coupling traces 104 and a second set of conductivecoupling traces 106 patterned (or formed) thereon. Conductive couplingtraces 104 and/or 106 can be utilized for coupling any sensing elements(not shown) or conductive traces that would form a sensing region 108with sensing circuitry 110 thereby enabling the operation of capacitivesensor apparatus 100. Conductive coupling traces 104 and 106 may eachinclude one or more conductive coupling elements or traces. Embodimentsof sensing element patterns in accordance with the invention can beimplemented to form sensing region 108.

Within FIG. 1, the capacitive sensor apparatus 100 can also beimplemented as a capacitive touchpad device. For example, substrate 102of capacitive sensor apparatus 100 can be implemented with, but is notlimited to, one or more opaque materials that are utilized as asubstrate for a capacitive touchpad device.

FIG. 2 is a plan view of an exemplary capacitive sensor pattern 200 inaccordance with embodiments of the invention. Specifically, sensorpattem 200 includes sensing elements 202, 204, and 206 having threephases which can be utilized as part of a two-dimensional capacitivesensor apparatus (e.g., 100), such as but not limited to, a touch sensorand/or a touchpad. When electrically coupled, sensor pattem 200 providespositioning information from a sensor pattern that has substantiallyparallel traces (or elements) with no crossovers. The positioninginformation can be derived from which of the sensing elements detects anobject (e.g., a user's finger, a probe, and the like), and theproportional strength of the signals on sensing elements 202, 204, and206.

Specifically, sensing elements 202, 204, and 206 can be oriented using asingle layer of conductive material such that they are substantiallyparallel to a first axis and their capacitive coupling to the sensorsurface can vary periodically along the length of each trace (or sensingelement). In one embodiment, the widths of the sensing elements 202,204, and 206 vary sinusoidally. For example, the widths of sensingelements 202, 204, and 206 can each be a sinusoidal function ofposition. However, the varying width of each sensing element 202, 204,and 206 can include all or a portion of a sinusoidal waveform.Additionally, the varying width of each sensing element 202, 204, and206 can include multiple sinusoidal waveforms or any other type ofwaveform. The sum of the widths of traces 202, 204, and 206 can also beimplemented as a substantial constant.

Within FIG. 2, the phases of traces 202, 204, and 206 can each beshifted relative to its neighbors, so that the sum of the traces 202,204, and 206 produces a complementary set of signals. The sensingelements 202, 204, and 206 can differ in phase by any angle (e.g.,substantially 24, 30, 36, 40, 45, 60, 72, 90, or 120 degrees, etc.).Within the present embodiment, sensing elements 202, 204, and 206 areeach implemented to include less than one cycle (or period) of asinusoidal waveform while each has a different phase. In this manner,each of the sensing elements 202, 204, and 206 produces a unique signalalong its length. Therefore, the combination of the output signalsproduced by the sensing elements 202, 204, and 206 can specificallyidentify the location of an object (e.g., a user's finger, a probe, astylus, etc.) along the length of sensor pattern 200. The sensingelements 202, 204, and 206 are located such that they are not requiredto overlap each other in order to determine a first location of anobject along the first axis of a two-dimensional space.

The shape and phase of the sensing elements 202, 204, and 206 can beimplemented in a wide variety of ways. For example, within the presentembodiment, if the waveform shape of sensing element 202 issubstantially equal to sin θ, then the waveform shape of sensing element204 may be substantially equal to sin (θ+120 degrees), while thewaveform shape of sensing element 206 may be substantially equal to sin(θ+240 degrees). Alternatively, the waveforms of sensing elements 204and 206 may each be offset from the waveform of sensing element 202 by2π3 radians. However, the phase and shape of the waveform of sensingelements 202, 204, and 206 are not in any way limited to the presentembodiment.

According to embodiments of the present invention, there are a widevariety of ways for determining a location (or position) of an object inrelation to the length of sensor pattern 200 using signals output bysensing elements 202, 204, and 206. For instance, FIG. 4 illustrates anexemplary signal strength chart 402 along with its conversion into polarcoordinates in accordance with embodiments of the invention. Forexample, suppose signal “A” is associated with sensing element 202 (FIG.2), signal “B” is associated with sensing element 204, and signal “C” isassociated with sensing element 206. As such, based on the signalstrength shown within chart 402, it can be determined that the object islocated along sensor 200 where sensing trace 204 is the widest, thesensing trace 202 is the second widest, and the sensing trace 206 is thethird widest. Therefore, within this example, the object is located nearthe right-hand end of sensor pattern 200.

More specifically, signal A corresponds to sensing element 202, signal Bcorresponds to sensing element 204, and signal C corresponds to sensingelement 206, as mentioned above. Further suppose that sensing elements(or traces) 202, 204, and 206 have been observed to give values A₀, B₀,and C₀, respectively, when no object is present or near sensor pattern200. As such, let a=A−A₀, b=B−B₀, and c=C−C₀. Therefore, determinationof the polar coordinates “h,” “r” and the angle θ that are associatedwith signals A, B, and C can be performed, as described below.

Within FIG. 4, the value of “h” corresponds to the height of the centerof a circle 404 upon which points 406, 408, and 410 can be located. Thepoints 406, 408, and 410 are associated with signals A, B, and C,respectively. The value of “r” corresponds to the radius of circle 404.The value of angle θ can be used to indicate the linear location (orposition) of an object in relationship to the length of sensor pattem200. Specifically, the value of height “h” can be determined by usingthe following relationship:h=(a+b+c)/3.  (1)

Once “h” has been determined, the radius “r” can then be determinedutilizing the following relationship:r=sqrt((2/3)×[(a−h)²+(b−h)²+(c−h)²]),  (2)where “sqrt” represents the square root function. Once “r” has beendetermined, the angle θ can then be determined utilizing one of thefollowing relationships:θ=sin⁻¹((a−h)/r)  (3)orθ=sin⁻¹((b−h)/r)  (4)orθ=sin⁻¹((c−h)/r).  (5)

Once the angle θ has been determined, it can then be converted into adistance that corresponds to a linear position measured along the lengthof sensor pattern 200 from one of its end points. For example, eachdegree of angle θ may be equal to a specific distance (e.g., a specificnumber of millimeters or inches) from one of the end points of sensorpattern 200. Alternatively, a lookup table may be utilized to ascertainthe distance that corresponds to the determined θ. The angle θ providesthe location of the center of the object along sensor pattern 200 whilethe “h” and the “r” can provide information regarding the size of theobject.

One of the advantages of determining the position along the first axis(e.g., X axis) of sensor pattern 200 in the manner described above isthat common-mode noise has no effect on the determination of “r” and θ.

Within FIG. 4, it is noted that angle θ can alternatively be determinedutilizing the following relationships:cos θ=a−(b+c)/2;  (6)sin θ=sqrt(3)/2(b−c);  (7)θ=A TAN2(cos θ, sin θ),  (8)where “ATAN2” represents the arc tangent function. The above threerelationships may be more convenient for use with a smallermicroprocessor.

The sensing elements 202, 204, and 206 of sensor pattern 200 can befabricated with any conductive material on any insulating substrate(e.g., 102). For example, this may include conventionalcopper/fiberglass printed circuit construction, ITO (indium tin oxide)patterned on glass, screen-printed conductor patterned on plastic, andthe like. The sensor pattern 200 may be used to detect objects on eitherside of the substrate onto which it is fabricated. To prevent detectionof signals of noise from one side of the substrate, a ground plane or adriven shield conductor may be utilized to shield that side.

There are advantages associated with the sensor pattern 200 of FIG. 2.For example, since the manufacture of sensor pattern 200 involves onelayer of conductive material, this reduces manufacturing costs relativeto the two-layer X-Y grids often used in touchpads. Additionally, in thecase of touch sensors, doing all the fabrication using only one layer ofconductive material eliminates low yield alignment steps. Furthermore,the optical properties of touch sensors can also benefit from the use ofonly one layer of substantially transparent conductive material, such asITO.

Sensor pattern 200 can be implemented with a greater number of sensingelements than the sensing elements 202, 204, and 206 shown. However, ifsensor pattern 200 is implemented with a greater number of sensingelements, the relationships described with reference to FIGS. 4 and 2are modified accordingly in order to determine “h,” “r” and θ.

Within FIG. 2, sensing elements 202, 204, and 206 of the sensor pattern200 can individually be coupled with sensing circuitry 110 (FIG. 1)utilizing conductive coupling traces 104 and/or 106. When coupled inthis manner, the sensor pattern 200 can be utilized to form the sensingregion 108.

FIG. 3 is a plan view of an exemplary capacitive sensor pattern 300 inaccordance with embodiments of the invention. When electrically coupled,sensor pattern 300 can provide two-dimensional positioning informationthat has substantially parallel traces (or elements) with no crossovers.Additionally, sensor pattern 300 includes a low-frequency set of sensingelements (e.g., 202, 204, and 206) and a high-frequency set of sensingelements (e.g., 302, 304, and 306). These two sets can work together toprovide “coarse” and “fine” positioning information.

Specifically, sensing elements 202, 204, and 206 can operate in anymanner similar to that described above to provide the “coarse”positioning information corresponding to the linear position of anobject (e.g., a user's finger, a probe, and the like) in relation tosensor pattern 300. For example, each of the signals associated withsensing elements 202, 204, and 206 can be utilized to determine theangle θ, as described above with reference to FIGS. 2 and 4. In thismanner, the “coarse” position along the first axis (e.g., X axis) ofsensor pattern 300 is determined to the first order.

The “fine” positioning information, or determination to the secondorder, can be obtained by utilizing sensing elements 302, 304, and 306.For example, each of the signals associated with sensing elements 302,304, and 306 can be utilized to determine a second value θ in a mannersimilar to that described herein with reference to FIGS. 2 and 4.Because sensing elements 302, 304, and 306 include four periods (orcycles) of sinusoidal waveforms, the determined second value of θ canrepresent. four different locations along traces 302, 304, and 306.However, because the “coarse” location is known with respect to sensingelements 202, 204, and 206, the second value of θ located closest to the“coarse” location can be used. In this manner, this second orderdetermination provides a finer resolution of the location (or position)of the object in relation to sensor pattern 300.

Within FIG. 3, sensing elements 202, 204, and 206 of sensor pattern 300can include a portion of a waveform, along with one or more waveforms.Additionally, sensing elements 302, 304, and 306 of sensor pattern 300can include any number of waveforms, or a portion of a waveform. Thesensing elements 302, 304, and 306 can be implemented in any manner thatis different than the manner that sensing elements 202, 204, and 206 ofsensor pattern 300 are implemented.

The sensing elements 202, 204, 206, 302, 304, and 306 of sensor pattern300 can be fabricated with any conductive material on any insulatingsubstrate (e.g., 102). For example, this may include conventionalcopper/fiberglass printed circuit construction, ITO patterned on glass,screen-printed conductor patterned on plastic, and the like. The sensorpattern 300 may be used to detect objects on either side of thesubstrate onto which it is fabricated. To prevent detection of signalsof noise from one side of the substrate, a ground plane or a drivenshield conductor may be utilized to shield that side.

Within FIG. 3, the “low-frequency” (or “coarse”) set of sensing elements(e.g., 202, 204, and 206) of sensor pattern 300 can be implemented witha greater number of sensing elements than that shown. Moreover, the“high-frequency” (or “fine”) set of sensing elements (e.g., 302, 304,and 306) of sensor pattern 300 can also be implemented with a greaternumber of sensing elements than that shown. However, if either the“coarse” set of sensing elements or “fine” set of sensing elements orboth are implemented with a greater number of sensing elements, therelationships described with reference to FIGS. 2 and 4 would bemodified accordingly in order to determine “h”, “r”, and θ.

It is appreciated that sensing elements 202, 204, 206, 302, 304, and 306of the sensor pattern 300 can individually be coupled with sensingcircuitry 110 (FIG. 1) utilizing conductive coupling traces 104 and/or106. When coupled in this manner, the sensor pattern 300 can be utilizedto form the sensing region 108. Sensor pattern 300 can be utilized inany manner similar to that described herein, but is not limited to such.

FIG. 5 is a plan view of an exemplary capacitive sensor pattern 500 inaccordance with embodiments of the invention. Specifically, sensorpattern 500 includes three repeated patterns similar to sensing elements202 a, 204 a, and 206 a having three phases which can be utilized aspart of a two-dimensional capacitive sensor apparatus (e.g., 100), suchas but not limited to, a touch sensor and/or a touchpad. Whenelectrically coupled, sensor pattern 500 can provide two-dimensionalpositioning information that has substantially parallel traces (orsensing elements) with no crossovers. The sensor pattern 500 can beutilized in any manner similar to that described herein with referenceto FIGS. 2 and 4. Additionally, any set of three adjacent traces canprovide the signals for determining first-axis positioning of an objectalong the length of sensor pattern 500. Within the present embodiment,sensor pattern 500 includes nine traces that allow for seven sets ofthree adjacent traces. Sensor pattern 500 can be utilized in any mannersimilar to that described herein, but is not limited to such.

The sensing elements 202 a, 204 a, 206 a, 202 b, 204 b, 206 b, 202 c,204 c, and 206 c of sensor pattern 500 have been implemented in adifferent manner than the sensing elements 202, 204, and 206 of FIGS. 2and 3. Specifically, each of the sensing elements 202 a, 204 a, 206 a,202 b, 204 b, 206 b, 202 c, 204 c, and 206 c does not include straightedges along its length. However, the sum of the widths of a set ofsensing elements (e.g., 202 a, 204 a, and 206 a) of sensor pattern 500can be implemented as a substantial constant.

Within FIG. 5, each of the nine sensing elements 202 a-206 c of thesensor pattern 500 can be individually coupled with sensing circuitry110 (FIG. 1) utilizing conductive coupling traces 104 and/or 106. Whencoupled in this manner, the sensor pattern 500 can be utilized to formthe sensing region 108. Furthermore, when coupled in this manner, sensorpattern 500 can provide positioning information along a first axis(e.g., X axis), as described herein, and along a second axis (e.g., Yaxis).

Specifically, each of the sensing elements 202 a-206 c of sensor pattern500 can be utilized for determining a second location along a secondaxis (e.g., Y axis) that can be substantially perpendicular (or notparallel) to the first axis (e.g., X axis). For example, if sensingelement 202 a and 204 a produce a strong signal while sensing element204 b and 206 b produce a very weak signal, the sensing circuitry (e.g.,110) coupled with the sensor pattern 500 can determine that an object islocated near sensing element 202 a in the Y direction of thetwo-dimensional space. Alternatively, if sensing element 206 c producesa strong signal while sensing element 202 b produces a very weak signal,the sensing circuitry can determine that an object is located below ornear sensing element 206 c in the Y direction of the two-dimensionalspace. In this manner, sensor pattern 500 can be utilized to provide twocoordinate positions associated with a two-dimensional space thatcorrespond to the position of an object in relation to the sensorpattern 500.

Within FIG. 5, all of the similar sensing elements (e.g., 202 a, 202 b,and 202 c) of sensor pattern 500 can be coupled together with sensingcircuitry 110 (FIG. 1) utilizing conductive coupling traces 104 and/or106. When coupled in this manner, the sensor pattern 500 can providepositioning information to the sensing circuitry 110 corresponding tothe first axis (e.g. X axis), but not along the second axis (e.g., Yaxis).

Sensor pattern 500 can be implemented with a greater or fewer number ofsensing elements than shown within the present embodiment. Sensorpattern 500 and its sensing elements 202 a, 204 a, 206 a, 202 b, 204 b,206 b, 202 c, 204 c, and 206 c can be implemented in any manner similarto that described herein, but is not limited to such.

Within FIG. 5, each set (e.g., 206 a, 202 b, and 204 b) of the sensingelements (e.g., 202 a-206 c) of sensor pattern 500 can operate in anymanner similar to that described herein in order to provide thepositioning information corresponding to the linear position of anobject (e.g., a user's finger, a probe, and the like) in relation tosensor pattern 500. For example, each set of the signals associated witha set of sensing elements (e.g., 204 b, 206 b, and 202 c) can beutilized to determine the angle θ, as described above with reference toFIGS. 2 and 4. In this manner, the position (or location) along thefirst axis (e.g., X axis) of sensor pattern 500 can be determined.

FIG. 6 is a plan view of an exemplary capacitive sensor pattern 600 inaccordance with embodiments of the invention. Specifically, sensorpattern 600 includes five repeated patterns of a set of sensing elements202, 204, and 206 having three phases which can be utilized as part of atwo-dimensional capacitive sensor apparatus (e.g., 100), such as but notlimited to, a touch sensor and/or a touchpad. Additionally, sensorpattern 600 includes second axis (e.g., Y axis) sensing elements 602that are substantially parallel to the first axis, and interdigitatedwith each set of sensing elements 202, 204, and 206, and can be utilizedfor providing position information along the second axis. Sensor pattern600 can provide two-dimensional positioning information that hassubstantially parallel traces (or sensing elements) with no crossovers.Sensor pattern 600 can be utilized in any manner similar to thatdescribed herein, but is not limited to such.

Each of the similar first axis sensing elements (e.g., 202) of sensorpattern 600 can be coupled together and coupled with sensing circuitry110 (FIG. 1) utilizing, but not limited to, conductive coupling traces106. However, each similar first axis-sensing element can be coupledtogether and coupled with sensing circuitry utilizing conductivecoupling traces 104 and/or 106. Additionally, each of the second axissensing elements (e.g., 602) can be coupled independently to sensingcircuitry utilizing, but not limited to, conductive coupling traces 104.However, each of the second axis sensing elements 602 can be coupledindividually with sensing circuitry utilizing conductive coupling traces104 and/or 106. When coupled in this manner, the second axis sensingelements 602 can operate to provide positioning informationcorresponding to the second axis position of an object (e.g., a userfinger, a probe, a stylus, etc.) relative to sensor pattern 600.Therefore, when coupled in this manner, the sensor pattern 600 canprovide positioning information to the sensing circuitry correspondingto the first axis (e.g. X axis) along with the second axis (e.g., Yaxis). The second axis is not parallel to the first axis and may besubstantially perpendicular to it. The sensor pattern 600 can beutilized to form the sensing region 108.

Alternatively, each of the first axis sensing elements (e.g., 202, 204,and 206) of the sensor pattern 600 can be individually coupled withsensing circuitry 110 (FIG. 1) utilizing conductive coupling traces 104and/or 106. When coupled in this manner, the sensor pattern 600 can beutilized to form the sensing region 108. Moreover, when coupled in thismanner, the first axis sensing elements (e.g., 202, 204, and 206) ofsensor pattern 600 can provide positioning information for both thefirst axis (e.g., X axis) and second axis (e.g., Y axis) since eachtrace can produce a signal that is individually detected by the sensingcircuitry. However, when coupled in this manner, sensor pattern 600 canbe implemented without the second axis sensing elements 602.

Sensor pattern 600 can be implemented with a greater or fewer number ofsensing elements than shown within the present embodiment. Sensorpattern 600 and its sensing elements can be implemented in any mannersimilar to that described herein, but is not limited to such.

Within FIG. 6, each set of the first axis sensing elements (e.g., 202,204, and 206) of sensor pattern 600 can operate in any manner similar tothat described herein in order to provide the positioning informationcorresponding to the linear position of an object (e.g., a user'sfinger, a probe, and the like) in relation to sensor pattern 600. Forexample, each set of the signals associated with a set of sensingelements (e.g., 202, 204, and 206) can be utilized to determine theangle θ, as described above with reference to FIGS. 2 and 4. In thismanner, the position (or location) along the first axis (e.g., X axis)of sensor pattern 600 is determined.

FIG. 7 is a plan view of an exemplary capacitive sensor pattern 700 inaccordance with embodiments of the invention. Specifically, sensorpattern 700 includes four repeated patterns of “coarse” and “fine” setsof sensing elements 202, 204, 206, 302, 304, and 306 which can beutilized as part of a two-dimensional capacitive sensor apparatus (e.g.,100), such as but not limited to, a touch sensor and/or a touchpad.Additionally, sensor pattern 700 includes second axis (e.g., Y axis)sensing elements 702 that are substantially parallel to the first axis,interdigitated with each set of sensing elements 202, 204, 206, 302,304, and 306, and can be utilized for providing position informationalong the second axis. Sensor pattern 700 can provide two-dimensionalpositioning information that has substantially parallel traces (orsensing elements) with no crossovers. Sensor pattern 700 can be utilizedin any manner similar to that described herein, but is not limited tosuch.

Each of the similar first axis sensing elements (e.g., 302) of sensorpattern 700 can be coupled together and coupled with sensing circuitry110 (FIG. 1) utilizing, but not limited to, conductive coupling traces104. However, each similar first axis-sensing element can be coupledtogether and coupled with sensing circuitry utilizing conductivecoupling traces 104 and/or 106. Furthermore, each of the second axissensing elements (e.g., 702) can be coupled independently to sensingcircuitry utilizing, but not limited to, conductive coupling traces 106.However, each of the second axis sensing elements 702 can be coupledindividually with sensing circuitry utilizing conductive coupling traces104 and/or 106. When coupled in this manner, the sensor pattern 700 canbe utilized to form the sensing region 108. Additionally, when coupledin this manner, the sensor pattern 700 can provide positioninginformation to the sensing circuitry corresponding to the first axis(e.g. X axis) along with the second axis (e.g., Y axis). The second axisis not parallel to the first axis and may be substantially perpendicularto it.

Alternatively, each of the first axis sensing elements (e.g., 202, 204,206, 302, 304, and 306) of the sensor pattern 700 can be individuallycoupled with sensing circuitry 110 (FIG. 1) utilizing conductivecoupling traces 104 and/or 106. When coupled in this manner, the sensorpattern 700 can be utilized to form the sensing region 108. Furthermore,when coupled in this manner, the first axis sensing elements (e.g., 202,204, 206, 302, 304, and 306) of sensor pattern 700 can providepositioning information for both the first axis (e.g., X axis) andsecond axis (e.g., Y axis) since each trace can produce a signal that isindividually detected by the sensing circuitry. However, when coupled inthis manner, sensor pattern 700 can be implemented without the secondaxis sensing elements 702.

Sensor pattern 700 can be implemented with a greater or fewer number ofsensing elements than shown within the present embodiment. Sensorpattern 700 and its sensing elements can be implemented in any mannersimilar to that described herein, but is not limited to such.

Within FIG. 7, each set of the first axis sensing elements (e.g., 202,204, 206, 302, 304, and 306) of sensor pattern 700 can operate in anymanner similar to that described herein to provide the positioninginformation corresponding to the linear position of an object (e.g., auser's finger, a probe, and the like) in relation to sensor pattern 700.For example, each set of the signals associated with a set of sensingelements (e.g., 202, 204, and 206) can be utilized to determine theangle θ, as described above with reference to FIGS. 2 and 4. In thismanner, the position (or location) along the first axis (e.g., X axis)of sensor pattern 700 is determined.

FIG. 8 is a plan view of an exemplary capacitive sensor pattem 800 inaccordance with embodiments of the invention. Specifically, sensorpattem 800 includes guard traces 802 and 804 along with five repeatedpatterns of sensing elements 202 a, 204 a, and 206 a having three phaseswhich can be utilized as part of a two-dimensional capacitive sensorapparatus (e.g., 100), such as, but not limited to, a touch sensorand/or a touchpad. When electrically coupled, sensor pattern 800 canprovide two-dimensional positioning information that has substantiallyparallel traces (or sensing elements) with no crossovers. The sensorpattern 800 can be utilized in any manner similar to that describedherein, but is not limited to such.

The five repeated patterns of sensing elements 202 a, 204 a, and 206 acan operate in any manner similar to sensor pattern 500 of FIG. 5,described herein. However, sensor pattern 800 of FIG. 8 also includesguard traces 802 and 804 which are located at the “top” and “bottom,”respectively, of sensor pattern 800 thereby enabling the “edge” sensingelements located near them to operate in a manner similar to thosesensing elements more centrally located within sensor pattern 800 (here,“top” and “bottom” are relative terms). The guard traces 802 and 804 maybe electrically driven, grounded, and/or held at a substantially fixedor constant potential in accordance with embodiments of the presentinvention.

For example, guard traces 802 and 804 of FIG. 8 may be coupled toground; in this manner, guard traces 802 and 804 are functioning asgrounded traces. Alternatively, guard traces 802 and 804 may be coupledto a constant potential signal; in this manner, guard traces 802 and 804are functioning as constant potential traces. Guard traces 802 and 804may also be actively driven; in this manner, guard traces 802 and 804are functioning as driven guard traces. Guard traces 802 and 804 may beimplemented in a wide variety of ways in accordance with the presentembodiment.

Guard traces (or grounded or fix potential traces) similar to guardtraces 802 and 804 can also be included as part of or with any sensingpattern described herein.

FIG. 9 is a plan view of an exemplary loop capacitive sensor pattern 900in accordance with embodiments of the invention. Specifically, sensorpattern 900 includes two sets of concentric loop patterns of threesensing elements 202 d, 204 d, and 206 d having three phases which canbe utilized as part of a two-dimensional capacitive sensor apparatus(e.g., 100), such as but not limited to, a touch sensor and/or atouchpad. When electrically coupled, sensor pattern 900 can providecontinuous two-dimensional positioning information that has sensingelements with varying width and no crossovers. The sensor pattern 900can be utilized in any manner similar to that described herein, but isnot limited to such.

Specifically, each of the sensing elements 202 d, 204 d, and 206 d hasvarying width and form a substantially circular (or loop) pattem. It isnoted that a loop pattern may include any closed loop sensor patternshape (e.g., circle, square, rectangle, triangle, polygon, etc.), radialarc sensor pattern, a semi-circle sensor pattem, and/or any sensorpattern that is not substantially in a straight line. The sensingelements 202 d, 204 d, and 206 d are not required to overlap each otherin order to determine an angular position φ of an object relative to thesubstantially circular pattern (e.g., loop) in a two-dimensional space.The angular position φ starts at an origin 902 which can be locatedanywhere associated with sensor pattern 900. The sensing elements 202 d,204 d, and 206 d provide a cumulative output signal that issubstantially constant at different locations along the traces 202 d,204 d, and 206 d.

Within FIG. 9, the sensing elements 202 d, 204 d, and 206 d can eachinclude a conductive trace. Furthermore, each set of sensing elements(e.g., 202 d, 204 d, and 206 d) can be used for determining a radialposition “R” of the object relative to the loop in the two-dimensionalspace.

Each of the sensing elements (e.g., 202 d, 204 d, and 206 d) of thesensor pattern 900 can be individually coupled with sensing circuitry110 (FIG. 1) utilizing conductive coupling traces 104 and/or 106. Whencoupled in this manner, the sensor pattern 900 can be utilized to formthe sensing region 108. Furthermore, when coupled in this manner, sensorpattern 900 can provide positioning information along the angularposition φ and the radial position R.

Alternatively, all similar sensing elements (e.g., 202 d) of sensorpattern 900 can be coupled together and coupled with sensing circuitry110 (FIG. 1) utilizing conductive coupling traces 104 and/or 106. Whencoupled in this manner, the sensor pattern 900 can provide positioninginformation to the sensing circuitry corresponding to the angularposition φ, but not of the radial position R. The radial position R canbe determined in any manner similar to the way the second axis positioncan be determined, as described herein.

Sensor pattern 900 can be implemented with a greater or fewer number ofsensing elements than shown within the present embodiment. For example,sensor pattern 900 can be implemented with a single set of sensingelements 202 d, 204 d, and 206 d. Alternatively, sensor pattern 900 canbe implemented with multiple sets of sensing elements 202 d, 204 d, and206 d. Sensor pattern 900 and its sensing elements can be implemented inany manner similar to that described herein, but is not limited to such.

Within FIG. 9, each set of the sensing elements (e.g., 202 d, 204 d, and206 d) of sensor pattern 900 can operate in any manner similar to thatdescribed herein in order to provide the positioning informationcorresponding to the angular position φ of an object (e.g., a user'sfinger, a probe, a stylus, and the like) in relation to sensor pattern900. For example, each set of the signals associated with a set ofsensing elements (e.g., 202 d, 204 d, and 206 d) can be utilized todetermine the phase angle θ, in a manner similar to that describedherein with reference to FIGS. 2 and 4. Once the phase angle θ has beendetermined, it may be converted into a geometric position angle φrelative to the origin 902. In this manner, the angular position φ of anobject is determined relative to sensor pattern 900.

The “coarse” or “fine” waveform patterns may have wavelengths thatdiffer from the circumference of the loop sensor.

FIG. 10 is a plan view of an exemplary loop capacitive sensor pattern1000 in accordance with embodiments of the invention. Specifically,sensor pattern 1000 includes two sets of concentric loop patterns offour sensing elements 202 e, 204 e, 206 e, and 1002 having four phaseswhich can be utilized as part of a two-dimensional capacitive sensorapparatus (e.g., 100), such as but not limited to, a touch sensor and/ora touchpad. When electrically coupled, sensor pattern 1000 can providecontinuous two-dimensional positioning information that has sensingelements with varying width and no crossovers. The sensor pattern 1000can be utilized in any manner similar to that described herein, but isnot limited to such.

Specifically, each of the sensing elements 202 e, 204 e, 206 e, and 1002has varying width and form a substantially circular (or loop) pattern.Sensing element 1002 can operate and be implemented in any mannersimilar to that described herein with reference to a sensing element. Aloop pattern can include any closed loop sensor pattern shape (e.g.,circle, square, rectangle, triangle, polygon, etc.), radial arc sensorpattern, a semi-circle sensor pattern, and/or any sensor pattern that isnot substantially in a straight line. The sensing elements 202 e, 204 e,206 e, and 1002 are not required to overlap each other in order todetermine an angular position φ of an object relative to thesubstantially circular pattern (e.g., loop) in two-dimensional space.The angular position φ starts at an origin 1004 which can be locatedanywhere associated with sensor pattern 1000. The sensing elements 202e, 204 e, 206 e, and 1002 provide a cumulative output signal that issubstantially constant at different locations along the traces 202 e,204 e, 206 e, and 1002.

Within FIG. 10, the sensing elements 202 e, 204 e, 206 e, and 1002 caneach include a non-conductive region formed by two or more adjacentelements. Additionally, the sensing elements 202 e, 204 e, 206 e, and1002 can each include a conductive trace. Furthermore, each set ofsensing elements (e.g., 202 e, 204 e, 206 e, and 1002) can also be usedfor determining a radial position “R” of the object relative to thepattern 1000 in the two-dimensional space.

Each of the sensing elements (e.g., 202 e, 204 e, 206 e, and 1002) ofthe sensor pattern 1000 can be individually coupled with sensingcircuitry 110 (FIG. 1) utilizing conductive coupling traces 104 and/or106. When coupled in this manner, the sensor pattern 800 can be utilizedto form the sensing region 108. Furthermore, when coupled in thismanner, sensor pattern 1000 can provide positioning information alongthe angular position φ and the radial position R.

Alternatively, all similar sensing elements (e.g., 202 e) of sensorpattern 1000 can be coupled together and coupled with sensing circuitry110 (FIG. 1) utilizing conductive coupling traces 104 and/or 106. Whencoupled in this manner, the sensor pattern 1000 can provide positioninginformation to the sensing circuitry corresponding to the angularposition φ, but not of the radial position R. The radial position R canbe determined in any manner similar to the way the second axis positioncan be determined, as described herein.

Sensor pattern 1000 can be implemented with a greater or fewer number ofsensing elements than shown within the present embodiment. Sensorpattern 1000 and its sensing elements can be implemented in any mannersimilar to that described herein, but is not limited to such.

Within FIG. 10, each set of the sensing elements (e.g., 202 e, 204 e,206 e, and 1002) of sensor pattern 1000 can operate in any mannersimilar to that described herein in order to provide the positioninginformation corresponding to the angular position φ of an object (e.g.,a user's finger, a probe, a stylus, and the like) in relation to sensorpattern 1000. For example, each set of the signals associated with a setof sensing elements (e.g., 202 e, 204 e, 206 e, and 1002) can beutilized to determine the phase angle θ, in a manner similar to that asdescribed herein with reference to FIGS. 2 and 4. Once the phase angle θhas been determined, it may be converted into a geometric position angleφ, relative to the origin 1004. In this manner, the angular position φof an object relative to sensor pattern 1000 is determined.

FIG. 11 is a plan view of an exemplary loop capacitive sensor pattern1100 in accordance with embodiments of the invention. Specifically,sensor pattern 1100 includes substantially “fixed” width sensingelements 1104, 1106, and 1108 along with four sets of concentric looppatterns of three sensing elements 202 f, 204 f, and 206 f having threephases which can be utilized as part of a two-dimensional capacitivesensor apparatus (e.g., 100), such as but not limited to, a touch sensorand/or a touchpad. When electrically coupled, sensor pattern 1100 canprovide continuous two-dimensional positioning information that includessensing elements with varying width and no crossovers. The sensorpattern 1100 can be utilized in any manner similar to that describedherein, but is not limited to such.

Each of the “fixed” width sensing elements 1104, 1106, and 1108 ofsensor pattern 1100 can be individually coupled with sensing circuitry110 (FIG. 1) utilizing conductive coupling traces 104 and/or 106. Whencoupled in this manner, sensing elements 1104, 1106, and 1108 can beutilized to provide positioning information to the sensing circuitry 110associated with the radial position R of an object (e.g., a user'sfinger, a probe, a stylus, and the like) in relation to sensor pattern1100. Additionally, each of the similar sensing elements of the foursets of sensing elements 202 f, 204 f, and 206 f can be coupled togetherand coupled with sensing circuitry 110 (FIG. 1) utilizing conductivecoupling traces 104 and/or 106. When coupled in this manner, the foursets of sensing elements 202 f, 204 f, and 206 f can provide positioninginformation to the sensing circuitry 110 corresponding to the angularposition φ of the object relative to an origin 1102.

Therefore, the constant width sensing elements 1104, 1106, and 1108 ofFIG. 11 can provide radial position R information to the sensingcircuitry corresponding to the object while the four sets of sensingelements 202 f, 204 f, and 206 f can provide angular position φinformation to the sensing circuitry associated with the sensor.

Each of the “fixed” width sensing elements 1104, 1106, and 1108 ofsensor pattern 1100 are implemented with a width that is substantiallyfixed or constant. The radial position R of sensor pattern 1100 can bedetermined in any manner similar to the way the second axis position canbe determined, as described herein. The origin 1102 can be locatedanywhere with respect to sensor pattern 1100.

FIG. 12 is a plan view of an exemplary loop capacitive sensor pattern1200 in accordance with embodiments of the invention. Specifically,sensor pattern 1200 includes two sets of non-concentric loop pattems ofthree sensing elements 202 g, 204 g, and 206 g having three phases whichcan be utilized as part of a two-dimensional capacitive sensor apparatus(e.g., 100), such as but not limited to, a touch sensor and/or atouchpad. When electrically coupled, sensor pattern 1200 can providecontinuous two-dimensional positioning information that has sensingelements with varying width and no crossovers. The sensor pattern 1200can be utilized in any manner similar to that described herein, but isnot limited to such.

Sensor pattern 1200 can operate in any manner similar to sensor pattern900 of FIG. 9. Furthermore, the sum of the widths of any three adjacenttraces (or sensing elements) of sensor pattern 1200 can be implementedas a substantial constant width. The sensor pattern 1200 can beimplemented with a greater or fewer number of sensing elements thanshown within the present embodiment. Sensor pattern 1200 and its sensingelements can be implemented in any manner similar to that describedherein, but is not limited to such.

FIG. 13 is a plan view of an exemplary “fishbone” capacitive sensorpattern 1300 in accordance with embodiments of the invention.Specifically, sensor pattern 1300 includes three repeated patterns ofsensing elements 202 h, 204 h, and 206 h having three phases which canbe utilized as part of a two-dimensional capacitive sensor apparatus(e.g., 100), such as but not limited to, a touch sensor and/or atouchpad. When electrically coupled, sensor pattern 1300 can providetwo-dimensional positioning information that has substantially paralleltraces (or sensing elements) with no crossovers. The sensor pattern 1300can be utilized in any manner similar to that described herein withreference to FIGS. 2 and 4. Additionally, sensor pattern 1300 can beutilized in any manner similar to that described herein, but is notlimited to such.

Specifically, sensing element 202 h includes extensions 1302 that aresubstantially parallel to each other and are substantially perpendicular(or non-parallel) to a first axis of sensing element 202 h. Theextensions 1302 cumulatively define an envelope the shape of a firstwaveform. The sensing element 204 h includes a plurality of extensions1304 that are substantially parallel to each other and are substantiallyperpendicular (or non-parallel) to the first axis of sensing element 204h. The extensions 1304 cumulatively define an envelope the shape of asecond waveform. The sensing element 206 h includes extensions 1306 thatare substantially parallel to each other and are substantiallyperpendicular (or non-parallel) to the first axis of sensing element 206h. The extensions 1306 cumulatively define an envelope the shape of athird waveform.

The repeated sets of sensing elements 202 h, 204 h, and 206 h can beused for determining a first location of an object (e.g., a user'sfinger, a probe, a stylus, and the like) in relation to sensor pattern1300 along the first axis of a two-dimensional space. Furthermore, therepeated sets of sensing elements 202 h, 204 h, and 206 h can be usedfor determining first and second locations of an object in relation tosensor pattern 1300 along the first axis and a second axis of thetwo-dimensional space, wherein the second axis is substantiallynon-parallel (or substantially perpendicular) to the first axis.

Within FIG. 13, sensor pattern 1300 can operate in any manner similar tosensor pattern 500 of FIG. 5. Furthermore, the sum of the widths of anythree adjacent traces (or sensing elements) of sensor pattern 1300 canbe implemented as a substantial constant width. The sensor pattern 1300can be implemented with a greater or fewer number of sensing elementsthan shown within the present embodiment. Sensor pattern 1300 and itssensing elements can be implemented in any manner similar to thatdescribed herein, but is not limited to such.

FIG. 14 is a plan view of an exemplary “fishbone” capacitive sensorpattern 1400 in accordance with embodiments of the invention.Specifically, sensor pattern 1400 includes three repeated patterns ofsensing elements 202 i, 204 i, and 206 i having three phases which canbe utilized as part of a two-dimensional capacitive sensor apparatus(e.g., 100), such as but not limited to, a touch sensor and/or atouchpad. When electrically coupled, sensor pattern 1400 can providetwo-dimensional positioning information that has substantially paralleltraces (or sensing elements) with no crossovers. The sensor pattern 1400can be utilized in any manner similar to that described herein withreference to FIGS. 2 and 4. Furthermore, sensor pattern 1400 can beutilized in any manner similar to that described herein, but is notlimited to such.

Specifically, sensing element 202 i includes extensions 1402 that aresubstantially parallel to each other and are substantially non-parallelto a first axis of sensing element 202 i. The extensions 1402cumulatively define an envelope the shape of a first waveform. Thesensing element 204 i includes extensions 1404 that are substantiallyparallel to each other and are substantially non-parallel to the firstaxis of sensing element 204 i. The extensions 1404 cumulatively definean envelope the shape of a second waveform. The sensing element 206 iincludes extensions 1406 that are substantially parallel to each otherand are substantially non-parallel to the first axis of sensing element206 i. The extensions 1406 cumulatively define an envelope the shape ofa third waveform.

The repeated sets of sensing elements 202 i, 204 i, and 206 i can beused for determining a first location of an object (e.g., a user'sfinger, a probe, a stylus, and the like) in relation to sensor pattern1400 along the first axis of a two-dimensional space. Furthermore, therepeated sets of sensing elements 202 i, 204 i, and 206 i can be usedfor determining first and second locations of an object in relation tosensor pattern 1400 along the first axis and a second axis of thetwo-dimensional space, wherein the second axis is substantiallynon-parallel (or substantially perpendicular) to the first axis.

Within FIG. 14, sensor pattern 1400 can operate in any manner similar tosensor pattern 500 of FIG. 5. Furthermore, the sum of the widths of anythree adjacent traces (or sensing elements) of sensor pattern 1400 canbe implemented as a substantial constant width. The sensor pattern 1400can be implemented with a greater or fewer number of sensing elementsthan shown within the present embodiment. Sensor pattern 1400 and itssensing elements can be implemented in any manner similar to thatdescribed herein, but is not limited to such.

Within FIGS. 13 and 14, second axis (e.g., Y axis) sensing elementshaving substantially constant width can be implemented as part of sensorpatterns 1300 and/or 1400. For example, second axis sensing elements canbe incorporated with sensor patterns 1300 and/or 1400 in any mannersimilar to that described herein with reference to FIGS. 6 and 7, but isnot limited to such.

FIG. 15 is a plan view of an exemplary “fishbone” capacitive sensorpattern 1500 in accordance with embodiments of the invention.Specifically, sensor pattern 1500 includes three repeated pattems ofsensing elements 202 j, 204 j, and 206 j having three phases which canbe utilized as part of a two-dimensional capacitive sensor apparatus(e.g., 100), such as but not limited to, a touch sensor and/or atouchpad. When electrically coupled, sensor pattern 1500 can providetwo-dimensional positioning information that has substantially paralleltraces (or sensing elements) with no crossovers. The sensor pattern 1500can be utilized in any manner similar to that described herein withreference to FIGS. 2 and 4, but is not limited to such. Moreover, sensorpattern 1500 can be utilized in any manner similar to that describedherein, but is not limited to such.

Specifically, sensing element 202 j includes extensions 1502 that aresubstantially parallel to each other and are substantially perpendicularto a first axis of sensing element 202 j. The extensions 1502 can eachbe implemented with a different width that slightly varies with itsneighboring extension. As such, a first waveform is defined by thevarying widths of the extensions 1502. The sensing element 204 jincludes extensions 1504 that are substantially parallel to each otherand are substantially perpendicular to the first axis of sensing element204 j. The extensions 1504 can each be implemented with a differentwidth that slightly varies with its neighboring extension. Therefore, asecond waveform is defined by the varying widths of the extensions 1504.The sensing element 206 j includes a plurality of extensions 1506 thatare substantially parallel to each other and are substantiallyperpendicular to the first axis of sensing element 206 j. The extensions1506 can each be implemented with a different width that slightly varieswith its neighboring extension. As such, a third waveform is defined bythe varying widths of the extensions 1506.

Within FIG. 15, the extensions 1502 of sensing element 202 j areinterdigitated with the extensions 1504 of sensing element 204 j.Moreover, the extensions 1506 of sensing element 206 j areinterdigitated with the extensions 1504 of sensing element 204 j.

The repeated sets of sensing elements 202 j, 204 j, and 206 j can beused for determining a first location of an object (e.g., a user'sfinger, a probe, a stylus, and the like) in relation to sensor pattern1500 along the first axis of a two-dimensional space. Furthermore, therepeated sets of sensing elements 202 j, 204 j, and 206 j can be usedfor determining first and second locations of an object in relation tosensor pattern 1500 along the first axis and a second axis of thetwo-dimensional space, wherein the second axis is substantiallynon-parallel (or substantially perpendicular) to the first axis.

Within FIG. 15, sensor pattern 1500 can operate in any manner similar tosensor pattern 500 of FIG. 5. Additionally, the sensor pattern 1500 canbe implemented with a greater or fewer number of sensing elements thanshown within the present embodiment. Sensor pattern 1500 and its sensingelements can be implemented in any manner similar to that describedherein, but is not limited to such.

FIG. 16 is a plan view of an exemplary “fishbone” capacitive sensorpattern 1600 in accordance with embodiments of the invention.Specifically, sensor pattern 1600 includes four repeated patterns ofsensing elements 202 k, 204 k, and 206 k having three phases which canbe utilized as part of a two-dimensional capacitive sensor apparatus(e.g., 100), such as but not limited to, a touch sensor and/or atouchpad. When electrically coupled, sensor pattern 1600 can providetwo-dimensional positioning information that has substantially paralleltraces (or sensing elements) with no crossovers. The sensor pattern 1600can be utilized in any manner similar to that described herein withreference to FIGS. 2 and 4, but is not limited to such. Furthermore,sensor pattern 1600 can be utilized in any manner similar to thatdescribed herein, but is not limited to such.

Specifically, sensing element 202 k includes extensions 1602 that aresubstantially parallel to each other and are substantially non-parallelto a first axis of sensing element 202 k. The extensions 1602 can eachbe implemented with a different width that slightly varies with itsneighboring extension. As such, a first waveform is defined by thevarying widths of the extensions 1602. The sensing element 204 kincludes extensions 1604 that are substantially parallel to each otherand are substantially non-parallel to the first axis of sensing element204 k. The extensions 1604 can each be implemented with a differentwidth that slightly varies with its neighboring extension. Therefore, asecond waveform is defined by the varying widths of the extensions 1604.The sensing element 206 k includes a extensions 1606 that aresubstantially parallel to each other and are substantially non-parallelto the first axis of sensing element 206 k. The extensions 1606 can eachbe implemented with a different width that slightly varies with itsneighboring extension. As such, a third waveform is defined by thevarying widths of the extensions 1606.

Within FIG. 16, the extensions 1602 of sensing element 202 k areinterdigitated with the extensions 1604 of sensing element 204 k.Furthermore, the extensions 1606 of sensing element 206 k areinterdigitated with the extensions 1604 of sensing element 204 k.

The repeated sets of sensing elements 202 k, 204 k, and 206 k can beused for determining a first location of an object (e.g., a user'sfinger, a probe, a stylus, and the like) in relation to sensor pattern1600 along the first axis of a two-dimensional space. Additionally, therepeated sets of sensing elements 202 k, 204 k, and 206 k can be usedfor determining first and second locations of an object in relation tosensor pattern 1600 along the first axis and a second axis of thetwo-dimensional space, wherein the second axis is substantiallynon-parallel (or substantially perpendicular) to the first axis.

Within FIG. 16, sensor pattern 1600 can operate in any manner similar tosensor pattern 500 of FIG. 5. Furthermore, the sensor pattern 1600 canbe implemented with a greater or fewer number of sensing elements thanshown within the present embodiment. Sensor pattern 1600 and its sensingelements can be implemented in any manner similar to that describedherein, but is not limited to such.

FIG. 17 is a plan view of an exemplary capacitive sensor pattern 1700 inaccordance with embodiments of the present invention. In one embodiment,sensor pattern 1700 includes a number of electrically conductive sensingelements 1701, 1702, 1703, 1704, 1705 and 1706 that have widths thatvary and lengths that traverse a sensing region (e.g., sensing region108 of FIG. 1). The sensing elements 1701-1706 are similar to the typesof sensing elements previously described herein, such as sensingelements 202, 204 and 206 of FIG. 2. In one embodiment, the sensingelements 1701-1706 are adjacent each other; that is, they do notoverlap. In the illustrated embodiment, the widths of the sensingelements 1701 a, 1701 b and 1702-1706 are sinusoidal functions ofposition, although the present invention is not so limited.

With reference to FIG. 17, the sensing element 1701 includes a firstvariable-width portion 1701 a disposed adjacent a first edge of thesensing region, and a second variable-width portion 1701 b disposedadjacent a second edge of the sensing region opposite the first edge. Anadvantage of the sensor pattern 1700 is that the potential for anambiguous sensor response is reduced or eliminated, by making the sensorresponse along the edges of the sensing region more like the sensorresponse in the interior of the sensing region.

As shown in FIG. 18, the sensing elements 1702-1706 output a respectivesensor signal 1802, 1803, 1804, 1805 and 1806. A sensor signal 1801 athat is output from the first portion 1701 a and a sensor signal 1801 bthat is output from the second portion 1701 b are combined to provide asensor signal.

In the present embodiment, the sensor signals 1802 and 1805 are combined(signal “B”), the sensor signals 1803 and 1806 are combined (signal“C”), and the sensor signals 1801 a, 1801 b and 1804 are combined(signal “A”). Signals can be combined in a variety of ways. For example,the sensor signals can be combined by connecting the outputs of two ormore sensing elements to the same electrical conductor (e.g., aconductive coupling trace or lead wire). That is, with reference to FIG.18, sensing elements 1701 a and 1701 b can be electrically connected toa same conductor to combine the signals 1801 a and 1801 b.Alternatively, some measure of the strength of the sensor signals can bemathematically combined (e.g., added). That is, for example, acapacitance (or current, voltage, etc.) measured for signal 1801 a canbe added to a capacitance (or current, voltage, etc.) measured forsignal 1801 b.

The signals A, B and C can be used to determine a location (or position)of an object or finger relative to sensor pattern 1700 using, forexample, the methodology described above in conjunction with FIG. 4. Inaddition to determining position, or as an alternative to determiningposition, the rate of movement of an object or finger relative to sensorpattern 1700 can be determined. As mentioned above, the widths of thesensing elements 1701 a, 1701 b and 1702-1706 may be sinusoidalfunctions of position. In the embodiment of FIG. 17, a waveform of asingle cycle or period is illustrated. Finer rate measurements can beachieved by using waveforms having multiple cycles (see sensing elements302, 304 and 306 of FIG. 3, for example).

In one embodiment, the surface area of sensing element 1701 (consistingof the combined surface area of portions 1701 a and 1701 b) isapproximately equal to the surface area of sensing element 1704; thesurface area of sensing element 1702 is approximately equal to thesurface area of sensing element 1705; and the surface area of sensingelement 1703 is approximately equal to the surface area of sensingelement 1706. In one embodiment, the combined surface area of thesensing elements 1702 and 1705 is essentially the same as the combinedsurface area of sensing elements 1703 and 1706, which in turn isessentially the same as the combined surface area of sensing elements1701 and 1704. By balancing the surface areas of the sensing elements inthis manner, in an “idle” state (that is, in a state in which a fingeror object is not in proximity to the capacitive sensing apparatus), eachof the signals A, B and C will have approximately the same backgroundcapacitance, and would be expected to experience a similar response whena finger or object is placed in proximity. However, embodiments inaccordance with the present invention are not limited to equally sizedsensing elements.

In one embodiment, the surface area of the portion 1701 a isapproximately the same as the surface area of the portion 1701 b; thatis, the sensing element 1701 is divided into two, approximately equalportions 1701 a and 1701 b. However, the sensing element may instead bedivided into unequally sized portions.

In one embodiment, sensor pattern 1700 also includes a guard trace 1716along the perimeter of the sensing region. The guard trace 1716 may beelectrically driven, grounded, and/or held at a substantially fixed orconstant potential. The guard trace 1716 functions to reduce the effectof a fringing electrical field on the conductive coupling traceconnected to the sensing portions 1701 a and 1701 b, thereby reducingany mismatch between the various conductive coupling traces.

Although sensor pattern 1700 is illustrated as being rectilinear inshape, the present invention is not so limited. Other shapes, such asbut not limited to those described by the figures discussed above, maybe used. Also, although the sensing elements 1701-1706 are illustratedas traversing the sensing region in the larger (“length”) dimension, thepresent invention is not so limited. That is, the sensing elements1701-1706 may instead traverse the sending region in the shorter(“width) dimension.

FIG. 19 is a plan view of an exemplary capacitive sensor pattern 1900 inaccordance with embodiments of the present invention. In one embodiment,sensor pattern 1900 includes a number of electrically conductive sensingelement portions 1901, 1902, 1903, 1904, 1905 and 1906 that have widthsthat vary and lengths that traverse a sensing region. As will be seen bythe discussion below, in one embodiment, the sensing element portions1901 and 1906 are electrically coupled to constitute a first sensingelement; the sensing element portions 1902 and 1905 are electricallycoupled to constitute a second sensing element; and the sensing elementportions 1903 and 1904 are electrically coupled to constitute a thirdsensing element.

The sensing element portions 1901-1906 are similar to the types ofsensing elements previously described herein, such as sensing elements202 d, 204 d and 206 d of FIG. 9. In one embodiment, the sensing elementportions 1901-1906 are adjacent each other; that is, they do notoverlap.

In the illustrated embodiment, the sensing region is circular in shape(e.g., ring-shaped), with widths that vary in the radial direction R. Inthis embodiment, the perimeters 1911, 1912, 1913, 1914, 1915 and 1916 ofthe sensing element portions 1901-1906, respectively, form a series ofnested circles that have different center points.

The sensing element portions 1901-1906 output respective sensor signals(not shown). In one embodiment, the sensor signals generated by sensingelement portions 1903 and 1904 are combined to produce a first combinedsensor signal; the sensor signals generated by sensing element portions1902 and 1905 are combined to produce a second combined sensor signal;and the sensor signals generated by sensing element portions 1901 and1906 are combined to produce a third combined sensor signal. Asdiscussed in conjunction with FIG. 17 above, signals can be combined ina variety of ways. The three signals so produced can be used todetermine an angular position φ, measured from an arbitrarily selectedorigin 1910, and a radial position R, measured from the center point1950, of an object or finger relative to sensor pattern 1900. The radialand angular positions can be determined in a manner similar to thatdescribed above in conjunction with FIGS. 9 and 10. Furthermore, therate of movement of an object or finger relative to sensor pattern 1900can be determined.

In essence, the sensing element portions 1901-1906 are arranged in aparticular pattern within sensor pattern 1900, where that patterncorresponds to the manner in which the respective sensor signals arecombined. To illustrate, if the sensing element portions 1903 and 1904(which contribute to the first combined sensor signal) are eachidentified using the letter “A,” the sensing element portions 1902 and1905 (which contribute to the second combined sensor signal) are eachidentified using the letter “B,” and the sensing element portions 1901and 1906 (which contribute to the third combined sensor signal) are eachidentified using the letter “C,” then the sensing element portions1901-1903 form a first pattem CBA and the sensing element portions1904-1906 form a second pattern ABC. The first and second pattern aresaid to be bilaterally symmetrical about the median 1920, where themedian 1920 is approximately equidistant from the two edges 1930 and1940.

By arranging the sensing element portions 1901-1906 in the manner justdescribed, the number of conductive coupling traces can be reduced. Forexample, instead of six traces (one trace per sensing element portion),five traces can be used (sensing element portions 1903 and 1904 can beconnected to the same conductive coupling trace).

In one embodiment, the surface areas of the respective sensing elementsare sized so that each pair of coupled sensing element portions hasapproximately the same surface area as the other pairs of coupledsensing element portions. That is, in the embodiment of FIG. 19, thecombined surface area of sensing element portions 1901 and 1906 isessentially the same as the combined surface area of sensing elementportions 1902 and 1905, which in turn is essentially the same as thecombined surface area of sensing element portions 1903 and 1904. Bybalancing the surface areas of the sensing elements in this manner, inan “idle” state (that is, in a state in which a finger or object is notin proximity to the capacitive sensing apparatus), the aforementionedfirst, second and third combined signals will have approximately thesame background capacitance, and would be expected to experience asimilar response when a finger or object is placed in proximity.

The width (as measured in the radial direction) of each of the sensingelement portions 1901-1906, and in particular the widths of the adjacentand electrically coupled sensing element portions 1903 and 1904, can beselected so that the sensing elements are discrete enough to determinethe radial position of a finger or object proximate to the sensingregion.

Other shapes, such as but not limited to those described by the figuresdiscussed above, may be used instead of the circular shape illustratedin FIG. 19. For example, sensor pattern 1900 can be rectilinear inshape—in effect, though not necessarily in actual practice, the pattern1900 can be cut along origin 1910, for example, and then straightenedinto a rectangular shape, allowing for lengthening of the inner sensingelements relative to the outer sensing elements. If rectilinear, thewidths of the sensing element portions 1901-1906 may be sinusoidalfunctions of position, although the present invention is not so limited.The aforementioned ABC-CBA arrangement of the sensing elements in thefirst and second pattems, which provides bilateral symmetry about amedian that is equidistant from the edges of the sensing region, can bemaintained for shapes other than circular shapes.

Although described for six sensing element portions (constituting threesensing elements), the present invention is not so limited; that is,more than six or less than six sensing element portions can be used toform the three sensing elements (also, more than three sensing elementsmay be used). Furthermore, the sensing element portions may be arrangedin more than two bilaterally symmetrical patterns. For example, considera sensing apparatus that uses 12 sensing element portions. The 12sensing element portions may be grouped into three groups: the firstgroup consisting of the first three adjacent element portions, thesecond group consisting of the next six adjacent element portions, andthe third group consisting of the last three adjacent element portions.The six sensing element portions in the second group can be arranged ina first and second pattern CBA-ABC as described above, and the threesensing element portions in the first group can be arranged in a thirdpattern as FED with the three sensing element portions in the thirdgroup arranged in a fourth pattern as DEF. The first and second patternsare bilaterally symmetrical, and the third and fourth patterns arebilaterally symmetrical. Other arrangements of sensing element portionsare possible.

FIG. 20 is a plan view of an exemplary capacitive sensor pattern 2000 inaccordance with embodiments of the present invention. In general, sensorpattern 2000 includes a number of electrically conductive sensingelements or sensing element portions 2001, 2002, 2003, 2004, 2005 and2006. The sensing elements 2001-2006 are similar to the types of sensingelements previously described herein, such as sensing elements 202 d,204 d and 206 d of FIG. 9 or sensing element portions 1901-1906 of FIG.19.

The conductive coupling traces 2010 are routed through respective gapsin the surrounding sensing elements. That is, for example, a conductivecoupling trace connected to sensing element 2001 is routed through gapsin sensing elements 2002-2006, a conductive coupling trace connected tosensing element 2002 is routed through gaps in sensing elements2003-2006, and so on.

By routing the traces 2010 through gaps in the surrounding sensingelements, sensor pattern 2000 can be implemented in a single layer ofconductive material. Consequently, a second conductive layer for signalrouting, as well as vias connecting the conductive layers, can beeliminated, reducing manufacturing costs. Indeed, sensor pattern 2000can be manufactured using conventional printed circuit board techniquesto provide the sensing elements and coupling traces in the desiredpattern on the single conductive layer.

FIG. 21 is a close-up view of the region 2100 of FIG. 20, showing thevarious conductive coupling traces 2101, 2102, 2103, 2104, 2105 and 2106connected to the sensing elements 2001-2006, respectively. As would beexpected, the gap dimension (e.g., the gap width) in, for example,sensing element 2006 is greater than that of sensing element 2002,because only a single coupling trace passes through sensing element2002, while multiple coupling traces pass through sensing element 2006.Therefore, according to embodiments of the present invention, thedimensions of the conducting traces 2102-2106 are selected to compensatefor the size of the gap in the sensing element to which they areconnected.

For example, presuming the conductive traces and the sensing elementsare of the same depth, then the dimensions (e.g., length and width) ofconductive trace 2106 are selected such that an areal measure ofconductive trace 2106 is approximately equal to the surface area ofsensing element 2006 that is lost or displaced because of the routing ofthe other conductive traces. Similarly, the length and width ofconductive trace 2105 are selected such that an areal measure ofconductive trace 2105 is approximately equal to the surface area ofsensing element 2005 that is lost or displaced because of the routing ofthe other conductive traces. The dimensions of the other conductivetraces 2102-2104 are similarly selected.

There is not a gap in the sensing element 2001; thus, the dimensions ofconductive trace 2101 can be selected based on other designconsiderations. For example, in an embodiment in which it is desirablethat the surface area of each sensing element is approximately the same,then conductive trace 2101 can be dimensioned such that its surface areaplus the surface area of sensing element 2001 is approximately equal tothe combined surface area of conductive trace 2102 and sensing element2002, and so on.

By using the areal measures of the conductive traces to balance thesurface areas of the sensing elements in the manner described above, inan “idle” state (that is, in a state in which a finger or object is notin proximity to the capacitive sensing apparatus), each sensing element2001-2006 will have approximately the same background capacitance, andwould be expected to experience a similar response when a finger orobject is placed in proximity.

Other shapes, such as but not limited to those described by the figuresdiscussed above, may be used instead of the circular shape illustratedin FIG. 20. For example, sensor pattern 2000 can be rectilinear inshape.

In conclusion, embodiments in accordance with the present inventionpertain to capacitive sensing apparatuses that can reduce manufacturingcosts, can sense position unambiguously, and/or can provide balancedsignals across the various sensing elements.

The various sensor patterns described herein can each include anon-conductive region formed by two or more adjacent sensing elements.Furthermore, the various sensor patterns described herein may each beoperated with very few sensor channels. This can offer substantial costsavings if there is a desire to use a low pin-count package, or build asimplified sensor ASIC (application-specific integrated circuit) for acapacitive sensor device or apparatus.

Moreover, the various sensor patterns described herein can each providea capacitive sensing geometry that does not induce signal-to-noise ratioconcerns. Additionally, the sensor patterns may each be used to detectobjects on either side of the substrate onto which it is fabricated. Toprevent detection of signals of noise from one side of the substrate, aground plane or a driven shield conductor may be utilized with thesensor patterns to shield that side.

In addition, the features of the various embodiments described hereincan be used alone or in combination. That is, for example, the featuresdescribed for one embodiment of a sensor pattern may be appropriatelycombined with the features described for another embodiment of a sensorpattern.

Furthermore, the sensing region 108 of FIG. 1 is not necessarily limitedto the use of a single sensor pattern. In other words, multiple sensorsutilizing the same or different sensor patterns can be placed adjacentto each other within sensing region 108.

The foregoing descriptions of specific embodiments of the presentinvention have been presented for purposes of illustration anddescription. They are not intended to be exhaustive or to limit theinvention to the precise forms disclosed, and obviously manymodifications and variations are possible in light of the aboveteaching. The embodiments were chosen and described in order to bestexplain the principles of the invention and its practical application,to thereby enable others skilled in the art to best utilize theinvention and various embodiments with various modifications as aresuited to the particular use contemplated. It is intended that the scopeof the invention be defined by the claims appended hereto and theirequivalents.

1. A capacitive sensing apparatus comprising: a plurality ofelectrically conductive sensing elements that have widths that vary andlengths that traverse a sensing region, said sensing elements comprisinga first sensing element, a second sensing element and a third sensingelement, wherein said third sensing element comprises a firstvariable-width portion disposed adjacent a first edge of said sensingregion and a second variable-width portion disposed adjacent a secondedge of said sensing region opposite said first edge; wherein a firstsensor signal is output from said first sensing element and a secondsensor signal is output from said second sensing element, and wherein asensor signal output from said first portion and a sensor signal outputfrom said second portion are combined to provide a third sensor signal.2. The capacitive sensing apparatus of claim 1 wherein said first andsecond portions are connected to a same electrical conductor to providesaid third sensor signal.
 3. The capacitive sensing apparatus of claim 1wherein a measure of said sensor signal output from said first portionis added to a measure of said sensor signal output from said secondportion to provide said third sensor signal.
 4. The capacitive sensingapparatus of claim 1 wherein said first, second and third sensingelements do not overlap each other in said sensing region.
 5. Thecapacitive sensing apparatus of claim 1 further comprising circuitrycoupled to said plurality of sensing elements, said circuitry operableto use said first, second and third sensor signals to determine anunambiguous position along an axis in the lengthwise dimension of saidsensing region.
 6. The capacitive sensing apparatus of claim 5 whereinsaid position is also determined along an axis in the widthwisedimension of said sensing region.
 7. The capacitive sensing apparatus ofclaim 1 further comprising circuitry coupled to said plurality ofsensing elements, said circuitry operable to use said first, second andthird sensor signals to determine a rate of movement of an objectproximate to said sensing region.
 8. The capacitive sensing apparatus ofclaim 1 further comprising an electrode that forms the perimeter of anarea that includes said sensing region.
 9. The capacitive sensingapparatus of claim 1 wherein the surface areas of said first, second andthird sensing elements are substantially equal.
 10. The capacitivesensing apparatus of claim 1 wherein said sensing elements furthercomprise a fourth sensing element, a fifth sensing element and a sixthsensing element, wherein a fourth sensor signal output from said fourthsensing element and said first sensor signal are combined, a fifthsensor signal output from said fifth sensing element and said secondsensor signal are combined, and a sixth sensor signal output from saidsixth sensing element and said third sensor signal are combined.
 11. Acapacitive sensing apparatus comprising: a plurality of electricallyconductive sensing elements that have widths that vary and lengths thattraverse a sensing region, said sensing elements comprising: a firstsensing element comprising a first variable-width portion and a secondvariable-width portion that produce a combined first sensor signal; asecond sensing element comprising a third variable-width portion and afourth variable-width portion that produce a combined second sensorsignal; and a third sensing element comprising a fifth variable-widthportion and a sixth variable-width portion that produce a combined thirdsensor signal; wherein said first, third and fifth variable-widthportions are arranged in a first pattern and said second, fourth andsixth variable-width portions are arranged in a second pattern, whereinsaid first pattern and said second pattern are bilaterally symmetricalabout a median that is substantially equidistant from opposite edges ofsaid sensing region.
 12. The capacitive sensing apparatus of claim 11wherein said first and second variable-width portions are connected to asame first electrical conductor to provide said first sensor signal. 13.The capacitive sensing apparatus of claim 12 wherein said third andfourth variable-width portions are connected to a same second electricalconductor to provide said second sensor signal, and wherein said fifthand sixth variable-width portions are connected to a same thirdelectrical conductor to provide said third sensor signal.
 14. Thecapacitive sensing apparatus of claim 11 wherein a measure of a sensorsignal output from said first variable-width portion is added to ameasure of a sensor signal output from said second variable-widthportion to provide said first sensor signal.
 15. The capacitive sensingapparatus of claim 14 wherein a measure of a sensor signal output fromsaid third variable-width portion is added to a measure of a sensorsignal output from said fourth variable-width portion to provide saidsecond sensor signal, and wherein a measure of a sensor signal outputfrom said fifth variable-width portion is added to a measure of a sensorsignal output from said sixth variable-width portion to provide saidthird sensor signal.
 16. The capacitive sensing apparatus of claim 11wherein said first, second and third sensing elements do not overlapeach other in said sensing region.
 17. The capacitive sensing apparatusof claim 11 further comprising circuitry coupled to said plurality ofsensing elements, said circuitry operable to use said first, second andthird sensor signals to determine an unambiguous position in thelengthwise dimension of said sensing region.
 18. The capacitive sensingapparatus of claim 17 wherein said position is also determined in thewidthwise dimension of said sensing region.
 19. The capacitive sensingapparatus of claim 11 further comprising circuitry coupled to saidplurality of sensing elements, said circuitry operable to use saidfirst, second and third sensor signals to determine a rate of movementof an object proximate to said sensing region.
 20. The capacitivesensing apparatus of claim 11 wherein the surface areas of said first,second and third sensing elements are substantially equal.
 21. Thecapacitive sensing apparatus of claim 11 wherein said sensing region isring-shaped.
 22. The capacitive sensing apparatus of claim 11 whereinsaid sensing region is rectilinear in shape. 23-33. (canceled)
 34. Acapacitive sensing method comprising: receiving a first sensor signalthat is output from a first sensing element of a plurality ofelectrically conductive sensing elements; receiving a second sensorsignal that is output from a second sensing element of said plurality ofelectrically conductive sensing elements, wherein said plurality ofelectrically conductive sensing elements have widths that vary andlengths that traverse a sensing region, said plurality of sensingelements also comprising a third sensing element that comprises a firstvariable-width portion disposed adjacent a first edge of said sensingregion and a second variable-width portion disposed adjacent a secondedge of said sensing region opposite said first edge; and combining asensor signal output from said first portion and a sensor signal outputfrom said second portion to provide a third sensor signal, wherein saidfirst, second and third sensor signals are useful for determining anunambiguous position along an axis of said sensing region.
 35. Themethod of claim 34 wherein said first, second and third sensing elementsdo not overlap each other in said sensing region.
 36. The method ofclaim 34 wherein the surface areas of said first, second and thirdsensing elements are substantially equal.
 37. A system comprising: aplurality of electrically conductive sensing elements that have widthsthat vary and lengths that traverse a sensing region, said sensingelements comprising a first sensing element, a second sensing elementand a third sensing element, wherein said third sensing elementcomprises a first variable-width portion disposed adjacent a first edgeof said sensing region and a second variable-width portion disposedadjacent a second edge of said sensing region opposite said first edge;and sensing circuitry coupled to said plurality of sensing elements,said sensing circuitry operable for receiving a first sensor signal fromsaid first sensing element and a second sensor signal from said secondsensing element, said sensing circuitry also operable for receiving athird sensor signal comprising a sensor signal from said first portioncombined with a sensor signal from said second portion.
 38. The systemof claim 37 further comprising an electrode that forms the perimeter ofan area that includes said sensing region.
 39. A capacitive sensingapparatus comprising: means for sensing comprising a first means, asecond means and a third means that each have widths that vary andlengths that traverse a sensing region, wherein said third meanscomprises a first variable-width portion disposed adjacent a first edgeof said sensing region and a second variable-width portion disposedadjacent a second edge of said sensing region opposite said first edge;wherein a first sensor signal is output from said first means and asecond sensor signal is output from said second means, and wherein asensor signal output from said first portion and a sensor signal outputfrom said second portion are combined to provide a third sensor signal.